The Ligand Core and the Biochemistry Core have been consolidated and renamed the Chemistry Core. This Core will provide to MDRTC investigators a wide variety of radioimmunoassays, enzyme immunoassays, spectrophotometric and fluorometric assays, high pressure liquid chromatography analysis of catecholamines, and custom radiolabeling services. Most of the laboratory services that were offered by both core facilities during the past funding periods will continue to be offered by the Chemistry Core, although some of the less commonly ordered procedures have been deleted from the test repertoire. New initiatives that will enhance the ability of the MDRTC to study diabetes and related disorders include: (1) conversion of several of the existing radioimmunoassay procedures to the more cost effective enzyme immunoassay methods, development of a specific radioimmunoassay for the direct determination of proinsulin, and continued development of new assays and improvement of existing assay technology, (2) production of polyclonal antibodies directed against compounds of interest to individual investigators or to the Chemistry Core, e.g., aldose reductase, glutamic acid dehydrogenase, and plasma-borne insulin-like growth factor I (IGF-I) binding proteins, and (3) the determination of tissue concentrations of intracellular and membrane bound hormone and growth factor receptors. These initiatives will enhance the ability of MDRTC investigators to more effectively examine one of the fascinating areas of biological research, i.e., the role of hormones and growth factors in autocrine, paracrine and endocrine control of cell function.